Complete the following 2 reactions A & B by choosing appropriate reactants \([\mathrm{X}]\) & \([\mathrm{Y}]\).

The reactions shown are electrophilic aromatic substitution reactions, specifically diazo coupling reactions between a diazonium salt and an activated aromatic ring. In reaction A, benzenediazonium chloride reacts with [X] to form p-hydroxyazobenzene. This is a coupling reaction with phenol ($\text{C}_6\text{H}_5\text{OH}$) in an alkaline medium (indicated by $\text{OH}^{-}$). The phenol acts as the nucleophile, attacking the diazonium cation at the para position. In reaction B, benzenediazonium chloride reacts with [Y] to form p-dimethylaminoazobenzene. This is a coupling reaction with N,N-dimethylaniline ($\text{C}_6\text{H}_5\text{N}(\text{CH}_3)_2$) in an acidic medium (indicated by $\text{H}^{+}$). The dimethylamino group activates the benzene ring towards electrophilic substitution at the para position. Comparing these with the given options, [X] corresponds to $\text{C}_6\text{H}_5\text{OH}$ and [Y] corresponds to $\text{C}_6\text{H}_5\text{N}(\text{CH}_3)_2$. Answer: $[\mathrm{X}] = \mathrm{C}_6\mathrm{H}_5\mathrm{OH} \quad [\mathrm{Y}] = \mathrm{C}_6\mathrm{H}_5\mathrm{N}(\mathrm{CH}_3)_2$